1. Field of Invention
The present invention pertains to the field of information storage units. More particularly, this invention relates to providing an information storage unit using an array of electron beam emitters and an information storage medium movable relative to the emitters using a micro electro mechanical system.
2. Background
Electronic devices, such as palm computers, digital cameras and cellular telephones, are becoming more compact and miniature, even as they incorporate more sophisticated data processing and storage circuitry. Moreover, types of digital communication other than text are becoming much more common, such as video, audio and graphics, requiring massive amounts of data to convey the complex information inherent therein. These developments have created an enormous demand for new storage technologies that are capable of handling more complex data at a lower cost and in a much more compact package.
One response to this demand has been the development of ultra-high density storage devices, such as the one described in U.S. Pat. No. 5,557,596 granted to Gibson et al. on Sep. 17, 1996. This system provides for a plurality of electron emitters generating beams of electrons to information storage media areas on a movable rotor device to store and retrieve information. A micro mover, based on micro electro mechanical systems (MEMS) technology moves the rotor device relative to the electron emitters to enable parallel communications with selected storage media areas on the rotor. In the Gibson et al patent, an electron beam impacts storage media areas at different intensities, selectively altering some aspects of the storage material, such as by changing the state of the storage material between amorphous and crystalline phases or between different crystalline phases that could affect the conductivity of a diode device, for example.
There is a continued need for increased miniaturization and expanded ability to handle greater quantities of more complex data at a faster speed and in even more compact areas. Efforts are now underway to adapt technology disclosed in the Gibson et al patent to enable the storage of data on scale of nanometers to tens of nanometers, referred to as atomic resolution storage (ARS).
Several challenges arise in attempting to store data at this ARS level. The processes of information storage and retrieval are difficult tasks. Electron beams from emitters are too diffuse to impact ARS storage sites without being modified. On the ARS scale, reading and writing by electron beams are increasingly delicate operations much more likely to be affected by stray electrons, atoms or molecules. Establishing and maintaining a vacuum in the storage media areas are critical.
The present invention provides for an ARS package using electron emitters for information processing and providing information access by the movement of MEMS devices. Information is stored by multiple emitter devices providing tightly focused electron beams on storage media areas disposed on the surface of a movable rotor device. To function at the ARS level, the electron beams are focused by electron optics. Multiple parallel operations are conducted by a plurality of electron emitters selectively applying simultaneous electron beams on the storage media areas.
The rotor is moved relative to the emitters by a MEMS motor disposed on the rotor and a stator spaced adjacent to the rotor. Most of the electronics for the emitters and the rotor are disposed on the stationary stator, enabling greater density of electron beams from the emitter and storage media areas on the rotor.
The electronic control circuitry for the rotor and emitter are disposed primarily on the stator. The circuitry communicates between the emitter and the stator by conductive plugs on the rotor connecting to electrical pads on the stator and the emitter. Electrical leads extend from the ARS package to external connections to remote systems.
The ARS package of the present invention provides for spacers between the rotor and the emitter and between the rotor and the stator to maintain crucial spacing between these components. The rotor, emitter and stator are bonded together to form an integral unit. The ARS package is necessarily sealed to form a vacuum, so that electron emission can occur in controlled conditions in which the undesirable side effects of ionizing stray atoms or molecules are minimized. A getter is provided at a single location or distributed throughout the ARS package to maintain a substantial vacuum within the package.
One preferred embodiment provides an information storage unit functioning in a vacuum, wherein a data storage medium has an information storage area for storing and reading information thereon. An array of electron beam emitters is spaced from and in close proximity to the data storage medium for selectively directing a plurality of electron beams toward the data storage medium. Focusing optics between the array of electron beam emitters and the data storage medium focus each of the electron beams on one part of the information storage area of the data storage medium. A micro electromechanical motor associated with the data storage medium moves the data storage medium relative to the array of electron beam emitters, so that each of the emitters directs an electron beam selectively to a portion of the information storage area to read or write information therein. Electronic circuitry spaced from and in electronic communication with the array of electron beam emitters controls the operations of the array of electron beam emitters. A vacuum device in the information storage unit maintains the vacuum between the data storage medium and the array of electron beam emitters.
Another preferred embodiment provides an atomic resolution information storage unit, wherein a planar rotor device has an information storage area thereon for storing information. A planar array of electron beam emitters in close proximity to the rotor device selectively directs electron beams to the information storage area on the rotor device. Focusing optics between the array of electron beam emitters and the planar rotor device focus the plurality of electron beams each on one portion of the information storage area of the planar rotor device. A driven mechanism on the rotor device causes the rotor device to move relative to the array of electron beam emitters in a plane parallel to the plane of said array of electron beam emitters. A stator device is disposed in close proximity to the rotor device and is stationary relative to the moveable rotor device. A driver mechanism on the stator device electrostatically engages the driven mechanism to move the rotor device relative to the array of electron beam emitters, thereby enabling the array of electron beam emitters to read from or write to different portions of the information storage area on the rotor device. Electronic control circuitry is disposed on the stator device in electrical communication with the array of electron beam emitters to control the operation of the array of electron beam emitters. A vacuum device in the atomic resolution information storage unit maintains a vacuum between the information storage area and the array of electron beam emitters.
Multiple MEMS motors may be employed in the present invention to increase the capabilities of the system operation. In such case, the operation of the MEMS motors may be either coordinated or independent, depending on the application.
Other aspects and advantages of the present invention will become apparent from the following detailed description, which in conjunction with the accompanying drawings illustrates by way of example the principles of the present invention.